Many people argue that English spelling is simply awful. George Bernard Shaw reckoned that the English "spell it so abominably that no man can teach himself what it sounds like". It is easy to find words like their/there/they're with the same sounds but different spellings. Some words have unique spellings all of their own, such as colonel and yacht. Six out of 10 15-year-olds can't write 10 lines without making at least one spelling mistake and adults struggle with words such as accommodate and broccoli all their lives.

By contrast, Noam Chomsky, the greatest linguist of our time, claims the current spelling of English is 'a near optimal system'. He feels that spelling that departs from the pronunciation sometimes helps us to understand what we are reading. Silent letters like the 'g' in sign connect one word to others in which the letters are not silent, such as signature; the fact the past tense ending '-ed' is said in three different ways, 't' (liked), 'd' (played), 'id' (waited) but written in only one, '-ed', makes clear their common meaning.

The difference between Shaw and Chomsky comes down to how they think spelling works. One of its functions is indeed to show the sounds of words. The word dog links the letters to the sounds one by one - 'd', 'o' and 'g'. Italian or Finnish use such links virtually all the time. But in English the correspondence between letters and sounds is usually much less straight-forward. Sometimes one letter corresponds to several sounds; the letter 'a' for instance has three different sounds in brat, bravo and brave. Sometimes two letters link to one sound - the 'th' in thin or the 'ng' in wrong. The sequence of letters can be out of step with the sequence of sounds; the 'u' in guess shows the pronunciation of the letter 'g' which occurs before it. Our problems with spelling are often due to not knowing the rules, say the doubling of 'c' and 'm' in accommod-ation or the consonants that go before particular vowels - cemetery ('c' is pronounced 's' before 'e') versus camel ('c' is pronounced 'k' before 'a').

With some written symbols, you either know what they mean or you don't have any idea, say '£', '#' or '%'. You do not have to know how they are said to get their meaning. The second function of spelling is then to show what words mean. Common words like 'the' and 'of' connect directly to their meanings in our minds, rather than being convert-ed into sounds letter by letter. Unique words have to be rememb-er-ed as one-off spellings, such as sapphire or chamois leather (shammy). Some systems of writing, such as Chinese, work primarily by linking whole symbols to meanings in this way. To use English spelling, you have not only to connect letters and sounds but also to remember a host of individual words, whether frequent ones like 'an' or unusual ones like 'Beauchamp'. In other words, English uses spelling both for sounds as assumed by Shaw and for meaning as believed by Chomsky.

English spelling is far more systematic than most people sus-pect. The most well-known rule 'i before e except after c' applies to only 11 out of the 10,000 most common words of English - eight forms of receive, plus ceiling, receipt and perceive. Other less familiar rules work far better, for instance the rule that a surname with the same pronunciation as an ordinary word can take a double consonant, Hogg and Bunn rather than hog and bun, or have an extra 'e', Trollope and Wilde instead of 'trollop' and 'wild'.

The great asset of English has always been its flexib-ility. Start-ing with a stock of letters borrowed from the Romans, the Irish and German tribes, it has evolved with the Eng-lish language for 1500 years. In the Old English spoken by the Anglo-Saxons every letter corres-ponded to a sound in words such as fæder (father) and riht (right). After 1066 the system had to cope with a deluge of words derived from French and Latin, such as tricherie (treach-ery) and nice. Over the centuries it has adapted words from many other languages, including coffee from Arabic and Turkish, broccoli from Italian and sushi from Japanese. Whatever the language a word comes from, English spelling can handle it.

At the same time the pronunciation of English has been chang-ing. Some Old English sounds died out: the 'h' (pronounced like Scottish 'loch') in riht became the silent 'gh' in right. Long vowels changed their pronun-c-iation between Chaucer and Shake-speare, wine was once said as wean, stone as 'starn'. Punct-uat-ion marks were introduced and their use gradually stabil-ised, the apost-rophe last and most eccentric of all. Because of the changing pronunciation, the rules linking letters and sounds became more complicated and the numb-er of eccentric individual words people had to remember became greater. The sound-based spelling of past tense in barkt, changd and parted gave way to the uniform meaning-based spelling 'ed' in barked, changed and parted.

All this change and outside influence has meant that English spelling now presents a rich set of possibilities for our use and entertainment. Pop-groups call themselves: the Beatles, Eminem and Sugababes. Novelists hint at dialects - Wot sort of party was this you was boaf at, anyway? - and think up book titles Pet Semetary. Owners invent names for their houses such as Hi-da Way, for drugs such as Zyrtec, and for race-horses such as Nothin' Leica Dane. Text messages cut down the number of letters: Wot time r u goin 2 b home?

It is indeed important for the international use of English that it is not too closely tied to speech. People from Houston, Glasgow, Hong-Kong or Bristol understand each other's writing but might well not under-stand each other's speech. Much world business uses written Eng-lish although the writers are not native speakers. Over three quarters of research papers in biol-ogy are written in English, and more than half of all web pages. Spell-ing and punctuation seldom betray whether an English language news-paper comes from Sant-iago, Kuala Lumpur or Jerus-alem, apart from the choice between American and British styles of spelling in words such as labor/labour.

So do we need to get excited about the frequent mistakes that people make when using the English writing system? Mistakes don't necessarily prevent us understanding the message. We still know what cemetary, Mens Toilets or england mean. Spell-check--ers can now handle most of these mistakes without any trouble. A mistake that interferes with the meaning of the message is more serious. The writer may need help or the spelling system itself may need modify-ing. Yet we hard-ly notice similar problems in speech: people are not sent to speech therapy for mispronouncing odd words. No-one suggests that spoken English should be reformed because some people find it hard to say 'th' sounds. The most talented writers make spelling mistakes. Keats once spelled fruit as furuit, W.B. Yeats wrote pecul-iar-ities as peculer-aritys, and Hemingway wrote professional as proffess-ional. Does this detract in any way from their achieve-ments?

Our discussions of spelling often suggest that there is an ideal of perfect spelling that people should strive for. Correct spelling and punctuation are seen as injunc--tions carved on tablets of stone: to break them is to trans-gres-s the tacit commandments for civilised behav-iour. Spelling and punctuation can become an emotional rather than rational area of dispute. No individual or institution has ever had the right to lay down the rules of English spelling. Nor are public discussions usually based on accounts of how modern English spelling actually works, but on the traditional rules handed down from the grammarians of the 18th century. Attempts to meddle with the spelling without this kind of factual basis have often been disastrous in the past, land--ing us with the 'b' of debt and the 'c' of scissors.

The English writing system is the rich and fertile creation of those who use English. Its rules are not arbitrary commandments, but the ongoing, living response to how people can express their ideas in writ-ing in an ever-devel-oping and changing world. Rather than continually carping about the decline of the English language, as people have been doing since at least the 16th century, we should try to understand and develop the amazing resource that is available to us.